Question

Bag A contains 4 white balls and 3 black balls, while Bag B contains 3 white balls and 5 black balls. Two balls are drawn from Bag A and placed in Bag B. Then, what is the probability of drawing a white ball from Bag B?

Answer 1

Here, we have three cases

Case 1: Two balls drawn from Bag A are White.

Case 2: Two balls drawn from Bag A are Black. 

Case 3: Two balls drawn from Bag A are one White and other Black.

Comments

Bhai aapne itne short me kiya mujhe samjh nhi aya.

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Samajh nhi aya

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There are only 3 cases possible for drawing two balls from bag A. It can be either
(i) two white balls which can be selected in ^4C2 ways
or (ii) two black balls which can be selected in ^3C2 ways
or (iii) one white and one black ball which can be selected in ^4C1 x ^3C1 ways.
Since, balls are placed in bag B.
So,
In case (i), there is 5 white balls out of 10 balls
In case (ii), there is 3 white balls out of 10 balls
In case (iii), there is 4 white balls out of 10 balls
Since, probabilities of drawing ball are independent in each case. so we have to multiplied these probability to find the probability of drawing white ball from bag B.